Originally described from seaside dunes in France, Agaricus bernardii has since been found in other maritime ecosystems in Europe, on the Pacific and Atlantic coasts of our continent . . . and in Denver. Perhaps an enterprising Denver lawn care business imported sod or sand from a coastal area, or perhaps Agaricus bernardii is capable of adapting to diverse ecosystems.

The salient features of Agaricus bernardii--taught to me by Ellen Jacobson of the Colorado Mycological Society--include the sheathlike (rather than skirtlike) ring; the tough, red-staining flesh; the subscaly mature cap surface; and the inrolled cap margin. Microscopic features (see below) will confirm identification.

Description:

Ecology: Saprobic; growing alone, scattered, or gregariously in sand dunes, drainage areas near coastal and brackish waters, and under Monterey Cypress; also in lawns and grassy areas (and then sometimes forming fairy rings); summer and fall (or over winter in California); recorded along the Pacific and Atlantic coasts, and in Denver.